1. Field of the Invention
The present invention relates to a camera controllable with use of a control program, to which the program for controlling the operation of each camera mechanism is inputted from outside the camera and in which a plurality of operations are successively carried out in accordance with such program.
2. Description of the Related Art
Conventionally, there is a camera which has a function to cause each camera mechanism to operate through execution of programmed operations. In this type of camera, it is possible to change the contents of the program by sending from outside the camera to it a program intended to cause performance of operations other than the programmed operations stored in the camera.
The first technique of changing the aforesaid program contents is, as described in Japanese Patent Unexamined SHOWA Publication No. 64-2031 as filed by the applicant of this application to connect an external unit such as a computer to the camera, call a desired one control subroutine from among a plurality of control subroutines stored in a camera memory, and cause execution thereof, thereby independently causing execution of the control operation for each camera mechanism.
The second technique intended to serve the same purpose is, as described in Japanese Patent Unexamined HEISEI Publication No. 2-941, to successively call each control subroutine from a plurality of control subroutines stored in a camera memory and cause execution thereof.
By using the above techniques, it is possible to cause execution of a desired subroutine, corresponding to the operation of each camera mechanism, stored in the camera connected to the external unit, in a given sequential order. This makes it easy to analyze a failure of the camera as well as to check the operational state of the camera.
However, since the aforesaid change of the program contents is performed by reading-out or writing-in of a control subroutine, it is necessary that a person who has a high level of knowledge on the flowchart of program, or a repairman who has a similar level of knowledge on the system, performs such change through handling the external unit. For this reason, an ordinary user having no such knowledge is still unable to change the contents of the program.
Further, there exists a problem that even a person having such knowledge fails to cause the camera to operate unless he inputs the address of a control subroutine for an operation of camera desired, by himself, to be performed, with use of predetermined language and in accordance with predetermined procedures.
Accordingly, in the above-described techniques, it was necessary to determine beforehand the sequential order of calling a control subroutine when sequentially calling it, by use of an external unit, from among a plurality of control subroutines stored in a camera memory, so as to prevent the camera from performing an erroneous operation.
Further, in the above-described techniques, when an operator erroneously operates to call a control subroutine in a sequential order causing the camera to perform an abnormal operation, this erroneous operation becomes unavoidable because the camera has no mechanism to check such an erroneous operation. In case of a single lens reflex camera in particular, since the members or elements such as those of a shutter mechanism or mirror wind-up mechanism are connected with each other in a complicated manner, the above-mentioned abnormal operations sometimes destruct, or break, such members or elements inconveniently.